Portable radio transmitting and receiving set



' April 13, 1948. D. H. MITCHELL PORTABLE RADIO TRANSMITTING AND RECEIVING SET Filed Feb. 20, 1942 ll Sheets-Sheet l Time/J A. @2 41 e// April 13, 1948. D, MUG-{ELL 2,439,408

PORTABLE RADIO TRANSMITTING AND RECEIVING SET Filed Feb. 20, 1942 11 Sheets-Sheet 2 a a W April 13, 1948. n-g 2,439,408

PORTABLE RADIO TRANSMITTING AND RECEIVING SET April 13, 1948.

PORTABLE RADIO TRANSMITTING AND RECEIVING SET 0. H. MITCHELL 2,439,408

Filed Feb. 20, 1942 ll Sheets-Sheet 4 A97 I m 13 I l /y v MIKE April 13, 1948. 0. H. MITCHELL PORTABLE RADIO TRANSMITTING AND RECEIVING SET 11 Sheets-Sheet 5 Filed Feb. 20, 1942 April 13, 1948.

D. MITCHELL PORTABLE RADIO TRANSMITTING AND RECEIVING SET Filed Feb. 20, 1942 ll Sheets-Sheet 6 April 13, 1948. MH-CHELL 2,439,408

PORTABLE RADIO TRANSMITTING AND RECEIVING SET Filed Feb. 20, 1942 ll Sheets-Sheet 7 April 13, 1948. n. H. MITCHELL PORTABLE RADIO TRANSMITTING AND RECEIVING SET 11 Sheets-Sheet 8 Filed Feb. 20, 1942 April 13, 1948. MlTCHELL 2,439,408

PORTABLE RADIO TRANSMITTING AND RECEIVING SET Filed Feb. 20, 1942 ll Sheets-Sheet 9 k Q I x xx N x x x m mkw \Q KW AR 4 p I 11 Sheets-Sheet l0 #WJ 1 x, X

P a xq N X k Q a. F J.fi \Q L wur wm fipem m April 13, 1948. D.- H. MITCHELL PORTABLE RADIO TRANSMITTING AND RECEIVING SET :Filed Feb. 20, 1942 Jam/y A7 M'zie/Z April 13, 1948. D. H. MITCHELL PORTABLE RADIO TRANSMITTING AND RECEIVING SET 11 Sheets-Sheet l1 RAH,

Filed Feb 20. 1942 fiaezz/ar. 5. fcie/Z java/Q Patented Apr. 13, 1948 PORTABLE RADIO TRANSMITTING AND RECEIVING SET Donald H. Mitchell, Chicago, Ill., assignor to Motorola, Inc., a corporation of Illinois Application February 20, 1942, Serial No. 431,722

18 Claims.

This invention relates generally to radio apparatus and in particular to a portable selfcontained combination radio receiver and transmitter unit.

The combination portable radio receiver and transmitter units now generally used are not entirely satisfactory because of their bulk and weight, and the inconveniences encountered in setting them up for operation. In most instances these prior art sets are not self-containedas a package unit and usually include an earphone unit or an antenna unit which are separately attachable to the body of the set by extension wires or'the like. As a result these are not capable of operation immediately on reaching a new destination or while enroute to such destination, since some time must be used for assembling the earphone or the antenna units and for making various tuning and control adjustments. Further because of the bulk of the sets they are diiiicult to handle and generally too heavy to be manually supported while in operation. In fact many of them require special supporting means upon which the various parts of the set are relatively arranged in a manner to facilitate their use. The maneuverability and the flexibility of application of these sets to the various field demands required of sets of this type, such as in an army signal corps, police work and the like, is thus appreciably restricted. Even after the sets are assembled for operation considerable delay is usually involved in the transmission and reception of signals because of the time lost in changing from transmitting to receiving and vice versa. Also because of their relatively complicated structure, the component parts of the prior art sets are usually completely dismantled for servicing and replacement purposes. Another objection to these sets is that they are open to the atmosphere whereby their use on rainy days is generally impaired or restricted to places having suitable shelters therefor. Further these sets are generally unprotected against rough handling or dropping so that great care must be exercised at all times to prevent permanent injury thereto.

It is an object of this invention, therefore, to provide an improved radio apparatus.

Another object of this invention is to provide an improved combination radio receiver and transmitter unit.

A further object of this invention is to provide a portable self-contained radio receiver and transmitter set which is capable of being operated while held in one hand of the operator and in which the earphone and microphone units are relatively arranged as in a telephone set. 1;}

Yet another object of this invention is to provide radio apparatus which is completely waterproof so that it may be entirely submerged without in any way impairing its operation.

A still further object of this invention is to provide a portable radio receiver and transmitter set, which is capable of being supported in one hand and in but one position for either transmitting or receiving, and in which a manually operated switch for changing the set to operate as either a receiver or transmitter is arranged for manipulation by the hand supporting the set.

Another object of this invention is to provide a-portable radio receiver and transmitter set in which all of the parts comprising the set are contained within a single housing structure, and of a construction such that they may be easily and individually removed from the housing for replacement or servicing purposes.

Yet another object of this invention is to provide a self-contained portable combination radio receiving and transmitting set which is compact, light in weight, and in which all of the parts are completely protected so that the set is capable of withstanding rough treatment and heavy usage without injury thereto.

A still further object of this invention is to provide a portable radio transmitting and receiving set which can be supported for operation in one hand of the operator and which is immediately operable without requiring any preparatory assembly work or preliminary circuit ad- J'ustments.

A further object of this invention is to provide a portable radio receiving and transmitting system which can be eiiiciently operated by an unskilled operator.

A feature of this invention is found in the provision of a portable self-contained radio receiving and transmitting unit in which all of the component parts thereof are adapted to be completely enclosed and assembled within an elongated housing so that the set can be comfortably grasped in one hand for operating and transporting purposes.

Another feature of this invention is found in the provision of radio equipment capable of being completely enclosed within an elongated housing in which linearly movable contact means for longitudinally extending switch means within the housing is actuated by manual means on the out de of the housing movable substantially in 3 a direction normal to the linear movement of said contact means.

Yet another feature of this invention is found in the provision of portable radio receiving and transmitting apparatus in which the operating parts are relatively arranged to completely eliminate any long leads for electrically connecting the same. Circuit losses in the apparatus are thus reduced to a minimum.

A still further feature of this invention is found in the provision of a self-contained radio receiving and transmitting system in which the, battery energy supplied to the vacuum tubes is automatically decreased when the set is operating as a receiver so as to conserve the battery energy for transmitter operation. 4

Still another feature of this invention is found in the provision of radio equipment in which an antenna of telescopic or disappearing type is operatively associated with the radio power switch to actuate the same, with the relative extended positions of the antenna being utilized to indicate the control positions of the switch.

Further objects, features, and advantages of this invention will become apparent from the following description when taken in connection with the accompanying drawings in which:

2 direction of Fig. '1 shows the complete radio receiver andtransmitter unit of this invention supported for operation in but one hand of the operator;

Fig. 2 is a front perspective view of the radio unit of this invention as it appears when not in use;

Fig. 3 is a perspective view of the invention looking at one end thereof, with such one end being opened to show the relative. arrangement of the chassis unit and battery units, which comprise all of the component operating parts of the invention, in a single housing structure;

Fig. 4 is a plan view of one of the end covers for the housing structure;

Fig. 5 is a transverse sectional view through the housing structure showing the assembly of the battery units therein;

Fig. 6 is a plan view of the chassis unit, the unit being shown in actual size;

Fig. 7 is a side elevational view of a transparent insulating member which forms a part of the switch means for changing the operation of the combination set of this invention from a receiver to a transmitter and vice versa;

Fig. 8 is a plan detail view of the change-over switch means;

Fig. 9 is an elevational view of the chassis unit looking at one side thereof Fig. 10 is an elevational view of the chassis unitas seen from the other side thereof;

Fig. 11 is an elevational view of the chassis unit looking at one end thereof along the line ll-H and showing the clip means for retaining the receiver and the transmitter crystals in assembly position;

Fig. 12 is a fragmentary sectional view as seen along the line l2l2 in Fig. 10;

Fig. 13 is an elevational end view of the chassis unit as seen along the line l3-l3 in Fig. 10;

Fig. 14 is a transverse sectional view taken along the line |4-l4 in Fig. 6 showing a portion of the structure for supporting an antenna of telescopic type on the chassis unit;

Fig. 15 is a fragmentary sectional view as seen along the line I 5|5 of Fig. 14;

Fig. 16 is a fragmentary sectional view showing the assembly of the antenna with the housing l 4 unit in a fixed position within the housing structure; v

Fig. 17 is a fragmentary sectional detailed view showing the assembly of a projecting portionwith the lower section of the telescopic antenna;

Fig. 18 is a front view of an antenna coil utilized in this invention;

- Fig. 19 is a transverse sectional view taken approximately along the line |9--l9 of Fig. 9;

Fig. 20 is a sectional view taken along the line 20-20 in Fig. 19 showing the assembly of a socket portion for a. vacuum tube with a base member of the chassis unit;

Fig. 21 is a fragmentary sectional view taken along the line 2l--2l in Fig. 20 showing a combination resistor and condenser unit adapted for cooperative assembly with the tube socket of Fig. 20;

' of the unit shown in Fig. 22;

Fig. 24 is a transverse sectional view of the combination resistor and condenser unit as seen structure, and the means for holding the 01315 1 Fig. 28 is an elevational end view of the inductance unit of Fig. 26 taken along the line 2828 in Fig.26;

Fig. 29 is an elevational view of the inductance.

unit of Fig. 26 as seen along the line 29-29 in Fig. 26;

Fig. 30 is an elevational view of a base portion for the inductance unit in Fig. 26 as seen along the line 30-40 in Fig. 26;

Fig. 31 is a fragmentary sectional view showing the manually operated means for actuating the change-over switch means;

Fig. 32 is a side view of the complete unit of this invention showing the same ready for operation;

Fig. 33 is a fragmentary sectional view of the earphone means taken along the line 3333 in Fig. 32;

Fig. 34 is a transverse sectional view taken along the line 34-34 in Fig. 32 showing the microphone unit and its assembly within the housing structure relative to the chassis unit and battery units;

Fig. 35 illustrates diagrammatically a complete circuit for the unit of this'invention; Q

Fig. 36 illustrates diagrammatically a circuit showing the connection of the filaments for the vacuum tubes in the diagram of Fig. 35;

Fig. 37 illustrates diagrammatically the receiving circuit of the invention;

Fig. 38 illustrates diagrammatically the circuit for the tube filaments when the invention is operating as a receiver;

Fig. 39 illustrates diagrammatically the transmitter circuit for this invention; and

Fig. 40 illustrates diagrammatically the-circuit for the connection of the filaments of the vacuum tubes when the invention is functioning as a transmitter. In practicing this invention there is provide a portable self-contained combination radio receiver and transmitter set which is compact and light in weight so as to be easily carried about or supported in one hand. The set includes a chassis, battery, microphone and earphone units. each of which is of a preassembled construction and capable of separate assembly in or removal from a common housing. The housing has open ends which are closed by removable cover plates, the housing being divided into a plurality of longitudinally extending compartments for receiving corresponding ones of the chassis and battery units. On removal of the housing cover plates these units are immediately accessible for easy removal from the housing. The housing is of an elongated construction so that it can be readily grasped in one hand, the earphone and microphone units being relatively arranged thereon so that the set can be held in an operating position by the operator in a manner similar to that of the well known telephone set.

A single switch means is utilized to change the set over from operating as a receiver to a transmitter and vice versa. The switch means is assembled as a part of the chassis unit and is positioned entirely within the housing. A manually operated unit for actuating the change-over switch means projects outwardly from one side of the housing, and is arranged relative to the earphone and microphone units so as to be positioned below the one hand of the operator used in supporting the set in an operating position. It is necessary merely to press and release the change-over switch with such supporting hand to immediately change the set from a receiver to a transmitter and vice versa. The on and off control or energy supply switch for the combination set is actuated by the movement of the lower section of a disappearing antenna, which is assembled as a part of the chassis unit and has a portion thereof extending through one of the end cover plates for the housing. On pulling of the lower section of the antenna outwardly from the housing the control switch is turned on, so that the extension of the lower section of the antenna from the housing indicates that energy is being supplied to the set.

The set is adjusted to operate at a predeter mined frequency so that no tuning or volume adjustments are required in the field. The set is thus immediately operative on extending the lower section of the antenna to supply energy thereto. Because the set is easily supported in one hand to a common operating position for.

both receiving and transmitting, apparent that the set can be used at any time regardless of whether the operator has arrived at his destination or is still enroute to such destination. The operating portion for the switch means, the housing cover plates, and the earphone and microphone units are all in a waterproofed assembly relative to the housing so that the complete set can be submerged in water without injury thereto. Since the set is completely enclosed within a common housing structure it is capable of being subjected to considerable rough handling and abusive treatment without permanent injury thereto.

Referring to the drawings the combination radio receiver and transmitter set of this invention is illustrated in Figs. 2 and 3 as including an elongated housing 40 of substantially square cross section over its entire length and open at the ends 4| and 42 thereof. In order to make the complete set as light as possible in weight it is contemplated that the housing 40 be composed of aluminum or like material. The housing 4|! is divided longitudinally by partition members 43 and 44 into compartments 46, 41 and 48 (Figs.

it is readily 3, 5 and 34) for an "A" battery unit 48, a 3" battery unit BI, and a preassembled chassis unit 52, respectively. The batteries 49 and ii are the sole source of energy supply for the set. The batteries 48 and II have contacts 83 and 54, respectively, at one of their corresponding ends, which are positioned at the open end 4| 0! the housing 40. The contacts 53 and 54 are thus positioned in proximity ,to contacts 56 and 51 respectively, carried on an end wall 58 of the chassis unit. The chassis unit 52 is connected through jack connections 59 and BI to an earphone unit 62 and a microphone unit 63 (Fig. 3), respectively, which will be later fully described. The wires and connecting the latter two units with the chassis 52 at the connections 59 and Bi, respectively, are positioned in a space provided by 'an insulating spacing member 64 extended longitudinally of the "B" battery compartment 41 (Figs. 3 and 5).

The open end 4| of the housing 40 is closed by a door or cover plate 66 pivotally supported by hinge means 81 on the housing 40 and having contact bridges 68 and 69 carried on the inside thereof. On closing of the cover 66 the contacts 53 and 51 are connected together by the bridge member BI, and the contacts 54 and '56 are connected together by the bridge member 89. Wires for connecting the batteries 49 and 5| with the chassis unit 52 are thus entirely eliminated. The cover 66 is releasably locked in its closed position by a swing bolt ll pivoted at 12 to the housing. 40 and receivable within a slot 13 formed in a. projection 14 on the cover 66. With the shank portion of the bolt II positioned within the slot 18, tightening of the nut 16 clamps the cover 68 against the open end H of the housing.

The battery units 49 and SI are of unequal lengths. the B battery 5| being equal substantially to the length of the housing 40 while the "A", battery 49 is only about half the length of the 8" battery. The partition member 44 does not completely separate the compartments or I which are angularly spaced in a chambers 48 and 41 from each other but functions primarily as a separating partition between the two battery units. The configuration of the compartments 48 and 41 is such that only a corresponding battery unit will fit within a corresponding compartment. The battery units 49 and SI, therefore, cannot be inserted into a wrong compartment. Each of the battery units is inserted within its corresponding compartment in the housing 40 against the pressure of a corresponding coil spring 48A and SIA, respectively. The springs 49A and BIA are of conical form and similar in construction, the small ends thereof being extended within a corresponding compartment. Since each of the springs 49A and HA is of a similar construction and similarly assembled with the cover plate 11 for closing the end 42 of the housing 40, only the spring iii A will be referred toin the following description.

The cover plate 11 is of a molded construction and of a substantially dish-shape, the end wall portion thereof being integrally formed with laterally extending projections 18 (Figs. 4 and 5) circular arrangement for receiving the large end of the sprin H A within the confines thereof. The spring 5i A is retained within the confines of the projections 18 by means including a lug l9 integral with the cover plate I1 and having a radially pronged head portion 8|. The spring BIA at the large end thereof is formed with an extending portion I k 82 of eyelet form for receiving the lug 19 therein. The lug 19 is substantially in the circular arrangement or the rojections 18, with the head portion 9i having the prongs thereon bent toward the spring portion 82 to clamp the same against the cover 11. The spring SIA is thus retained against any movement relative to the cover 11. Since the battery BI is substantially equal in length to the housin 40 the small end of the spring HA is engaged directly against the inserted end 89 of the battery Iii and in electrical connection therewith to ground the same. However, because 01' the short length of the battery 49, the spring 49A is connected at the small end thereof with an extension member 94 which projectsaxially of the spring 49A and into the compartment 49. The inner end 86 of the extension member 84 (Fig. 5) carries a net disc or plate 81 for bearing against the inner end 88 of the battery 49. A contact 85 on the disc 81 is electrically connected with the battery 49 to ground the same. It is to be understood of course that the extension 84 may be made of any desired length to accommodate any size battery within the compartments 48 and 41. In order to keep track of the date at which the batteries 49 and 5! are changed there is provided an indicating card 50b (Fig. 3) carried in a frame 59a having a transparent cover therein. The card 50b is removable from the frame 59a only when the cover 66 is open to prevent its becoming lost.

The chassis unit 52 is of a preassembled construction and is shown in Figs. 6, 9, and 11 in actual size. The chassis unit 52 includes a frame member 95 of substantially L-shape integrally formed.- with a base portion 9| and a supporting portion 99. Carried in the supporting portion 89 and in a spaced relation longitudinally thereof are peanut vacuum tubes T|--T5, inclusive. Since each of the vacuum tubes is similarly assembled in the supporting portion 89 only the vacuum tube Tl will be referred to in the following description.

" As shown in Fig. '19 the tube TI is projected outwardly from the supporting portion 89 and transversely across the base portion 9| so as to be substantially within the confines of the dimensions defined by the portions 89 and 9!. The socket 92 for the tube TI is adapted to be received in an opening 99 in the supporting portion 89 and is provided near the socket end 94 thereof with a metal bracket 99 which fits flush against the inner side of the supporting portion 89. The end 91 of the socket projects outwardly from the supporting portion 89 and carries a plurality of connections 98 for connecting the tube elements into the radio circuit. The end 91 has mounted thereon an annular or ring-shaped combination resistor and condenser unit 99 which includes all of the resistor and condenser elements required in the circuit of the tube TI.

The combination unit 99 (Figs. 19 and 21-25, inclusive) consists of an annular insulating member ml of channel shape, the open end I82 thereof being closed by a fiat ring-shaped insulating cover I93. The unit 99 is shown in actual size in Figs. 22, 23 and 24 wherein it is seen that the annular member I0! is about one inch in diameter and about three eighths of an inch deep. Within the space provided in ring member lill are resistors R and condensers C, which are electrically connected together in a predetermined circuit arrangement to provide the desired circuit characteristics for the tube Tl. Connections I95 for connecting the resistors and condensers to the connections 98 are extended outwardly from the combination unit 99 through the end wall portion "9 thereof. 0! course all of the connections from the combination unit are not connected with the tube n a 99. Some of these connections are connected to other portions or the radio circuit. These connections, therefore, are connected with tie lugs 699a, secured to the body member 898 to facilitate. their connections with any other part of the radio circuit. With the condr- C and resistors R in position within the member its a suitableimpregnating compound such as was or the like, and indicated at W, is poured into the ring member i8l through the open side use thereof, the hardening of the wax retaining the positions of the elements and protecting the same against any short circuiting or exposure to moisture. The fibre ring IDS is then glued or otherwise suitably secured across the open end in! of the ring member ii. To facilitate the connecting of the combination unit 99 in the tube circuit and to indicate the manner in which the resistor and condenser elements are connected therein, a circuit diagram for the unit, indicated at 39, is applied on the outer periphery of the ring iti.

In the assembly of the tube Ti with the frame member there is utilized a grounding plate Hill which is positioned about the tube socket 92 and between the leg portion 89 of the frame member and the combination unit 99. As a result of the weight considerations in portable radio equipment the use oi heavy materials must be eliminated wherever possible. Because of this fact, the frame member 99 which is a relatively large member, is composed of an aluminum material. Aluminum, however does not readily bond with a solder material so as to provide an efficient electricalconnection. To overcome this objection to aluminum relative to its soldering characteristics while benefiting from the light weight thereof, the grounding plate i'ill is assembled therewith as will now be described. The plate 1 91 in one embodiment of the invention is composed of a brass material plated with silver which readily bonds with solder. The bracket member 96 for the socket 92, the supporting portion 89, and the plate member 891 are formed with aligned apertures to provide for their being riveted together. With the plate lfiiriveted with the supporting portion 89, and of a construction providing for its being soldered with other electrical connections of Mao tube circuit, the tube circuit is eniciently grounded to the frame member 95.

In the assembly of the combination unit 99 with the tube socket 92 the soldering of the connections I95 with the connections 98 on the socket 92 holds the combination unit in its assembly position on the socket. To initially retain the combination unit 99 in assembly position it may be cemented or glued to the grounding plate I01. Because of this compact assembly of the combination unit 99 with the tube unit, comprising the .tube Ti and socket 92, it is seen that all of the difliculty is usually encountered in the handling 7 and assembling of the condenser and resistor elements in a radio circuit. By virtue of the compact and insulated assembly of the elements in the unit 99, this unit can be conveniently arranged relative to the circuit in which it is used, and connections made therefrom to other portions of such circuit. Individual handling and assembling of the resistor and condenser elements in the connecting of the radio circuit is thus entirely eliminated, whereby to decrease the time usually required in making the connections and providing for more neat appearing and secure electrical connections.

Portable radio units are generally subjected to considerable hard use and rough handling so that in many instances the tubes are shaken loose from their supporting sockets. To retain the tube TI in its position within the socket 92 there is provided means indicated generally as I08, and including a clip member I 09 and a spring member III (Figs. 9 and 19). The clip member I09 is integrally constructed with a fiat portion having an aperture H2 therein and an angular portion comprising a pair of spaced legs H3 and a portion H4 connecting the legs intermediate their ends so that a substantially rectangularly shaped opening H6 is formed between the legs I I3. The spring I I I is of flat shape and is formed at one end with a C-shape or arcuate portion I IT. The opposite end of the spring III is riveted to the base portion 9| of the frame member 95. The arcuate end II! of the spring III is extended through the opening H6 in the clip member I09 in a manner such that the connecting portion I I4 of the clip member I09 is locked between the spring end II! and the base portion 9| while permitting pivotal movement of the clip member I09. On pivotal movement of the clip member I09 the legs II3 thereof function as a cam relative to the base portion 9I so as to raise and lower the spring end I I! relative to the base portion 9I. This action of the legs H3 varies the pressure exerted by the spring I II on the clip member I 09 at the connection portion I I4'. With the clip member positioned, as shown in Fig. 19, the legs II3 are bent outwardly away from the unsupported end I9I of the tube TI. Thus when the flat portion of the clip member I09 is in a substantially vertical direction the spring II I urges the clip member I09 toward the tube TI. The tube TI is provided with a protecting metal can or shield I2I having a projecting annular lip portion I22 in the top thereof for reception in the opening II2 in the clip member I09. By virtue of the tension applied on the clip member I09 by the spring II I the shield I2I is urged against the supporting portion 89, a rubber cushion I23 arranged between the end of the tube TI and the top of the shield I2I absorbing any shocks which might be passed to the tube TI and providing a yieldable connection between the clip member I09 and the tube. The cushion I23 thus retains the tube in a snug position regardless of the tolerance in tube lengths'for the same type of tube.

When it is desired to remove the tube TI from its socket 92 the clip member I09 is moved pivotallyaway from the tube TI to its dotted line position indicated in Fig. 19. When the clip member I09 is in this dotted line position the pressure of the spring III is applied in a reversed direction relative to the fiat portion of the clip member I09 because of the position of the legs H3. The spring thus acts to retain the clip member I09 in its fiat or unclamped position. By virtue of this construction of the clip means I08, therefore, the clip member I09 is capable of having a pressure applied thereon in one direction to retain the-tube TI in a supported position, and in an opposite direction to hold it in an open position and away from the tube TI. It is to be understood of course, and as is shown in Fig. 9, that a clip means I08 is provided for each of the tubes TI--T5, inclusive, to retain them on the supporting portion 89.

Also carried on the supporting portion 89 and extending transversely of the base portion BI is a first IF transformer L4 (Figs. 6 and 9) positioned intermediate the tubes T2 and T3, and a second IF transformer L5 arranged between the tubes T3 and T4. are of a similar construction, the windings in each thereof being wound on a powdered iron core and surrounded by a powdered iron sleeve to further increase their inductance. This type of construction gives a high inductance with a very small winding to provide in all an efllcient transformer of small size. The primary and secondary windings of the transformers are tuned by small adjustable mica trimmers, indicated at I24 and contained within a metal shield can I26 for each transformer.

Positioned intermediate the tubes TI and T2 and extending transversely of the base portion BI is an antenna coil LI (Figs. 6 and 18) extending through and carried on the supporting portion 89 of the frame member for the chassis unit 52. The antenna coil LI is of a solenoid type and is wound on a polystyrene body portion I5.

The chassis unit 52 also includes a crystal MI used when the set is operating as a receiver and a crystal M2 used when the set is operating as a transmitter (Figs. 9 and 6). The crystals MI and M2 are of a similar construction and are contained in plug-in type holders carried in the supporting portion 89 near the end I2'I of the chassis unit 52. It is contemplated that each of the crystal holders be suitably marked to correspond with an associated crystal so as to minimize the possibility of the crystals MI and M2 being interchanged during the assembly of the chassis unit. The crystals MI and M2 are extended transversely across the base portion 9| of the frame member 95 so that the free or unconnected ends thereof are positioned away from the supporting portion 89. To retain the crystais MI and M2 in their supported positions there is provided a clip member I28 (Figs. 9, 11 and 16) integrally formed from a single piece of fiat material, and having one end pivotally supported on axis means I29 normal to the plane of the base portion 9| and positioned substantially intermediate the ends of the crystals MI and M2 and to one side thereof. The unconnected portion I3I of the clip member I28 is of a form corresponding to the shape of the ends of the crystals with the free end of the portion I3I having a catch portion I32 thereon for irictionally engaging the crystals MI and M2 in a manner clearly shown in Fig. 16. When the crystals MI and M2 are to be removed the clip member I28 is swingable about its axis I29 outwardly and away from the end 121 of the frame member 95 so that the portion I3! of the clip member is entirely removed away from the ends of the crystals.

An RF choke L9 (Figs. 6 and 10) is carried in an insulating housing I33 connected to a bracket I34 supported on the base portion 89 and arranged in alignment with the crystals MI and M2 transversely oi the base portion 9|. The RF The transformers L4 and L5 11 amplifier tank condenser CI2 (Figs. 6 and 9) is also carried in the supporting portion 89 and is arranged between the superposed crystals MI and M2 and the tube TI. Positioned adjacent the tube T5 and mounted on the base portion 9| is an inductance L8 which functions as an audio output reacto for receiving and as a modulation choke for transmitting. The elements L3, L6

and C I2 will be further explained in connection with the description of the circuit diagrams in Figs. 35, 37 and 39. g

In the operation of the combination radio receiver and transmitter set of this invention, itis contemplated that a group of the sets be used for intercommunication purposes at a particular frequency. In other words, the members'of a particular group of operators who are to be in communication with each other, will have their sets tuned to the same frequency so that they ation of the set at a desired frequency that provision must be made for a corresponding frequency change in the R. F. circuits so that such two circuits may be tuned to resonance at the desired frequency. In accomplishing a tuning of the R. F. circuit in resonance with the antenna circuit, there is provided an inductance unit indicated as L2 (Figs. 6 and 26 to 30, inclusive) which includes a body portion I14 and a supporting portion I18 secured to the portion 89 of the chassis unit frame member 95 by rivets I11. The coil I8I for the inductance unit L2 is wound about the outer periphery of the body portion I14. The body portion I14 has an internal bore I18 of hexagonal shape for receiving therein for slidable but non-rotatable movement an iron core I19 in the form of a hexagonal nut. The threaded aperture I 82 in the nut I19 is engageable with a threaded insulating screw I83 having a slotted adjusting portion I84 at one end and a peripheral groove I86 formed at the opposite end I81 thereof. The end I81 of the screw I83 is of tapered form and projects outwardly from the body portion I14 for reception in an aperture I88 provided in the supporting portion I16.

The supporting portion I16 is comprised of three flat insulating members arranged back to :back with the intermediate insulator serving as a spacer for accommodating a loop spring I89 positioned between the outer two of the insulators. Side portions I9I of the spring I89 extend across the opening I88 (Fig. 30) so that on insertion of the tapered end I81 within the aperture I88 the spring portions I9I are initially spread apart and then snapped into engagement with the screw I83 at the recess I88 therein. The engagement of the spring I89 with the screw I83 prevents any axial movement of the screw on rotation thereof for adjusting the core I19 axially of the body portion I14. It is to be noted that the adjustable screw I83 remains in the same relative position with respect to the coil I8I and that the core moves only axially of the screw and entirely within the body portion I14. By virtue of this construction the hexagonal nut I19 is adjustable within the body portion I14 over the entire length of the screw I83, with the length of the screw I83 being defined essentially by the axial length of the body portion I14. A unit of relatively high variable inductance is thus provided which is very compact and capable of assembly in a minimum of space. An insulating cap or cover I15 is snap connected with the body portion I14 and has'an aperture I therein for receiving the screw adjusting portion I84. In the above-mentioned commercial embodiment adapted for operating over a frequency range of from 3500 to 6000 ko., only six inductance units L2 are required to cover this entire frequency range.

Along with the changing of the coil LI and inductance unit L2 for operation at a particular frequency the crystals MI and M2, of course, must also be changed. The relation of the crystals MI and M2 for a specified frequency will be taken up hereinafter in connection with the circuit diagrams in Figs. 35, 37 and 39. The operating frequency for the set is indicated on the card 5% (Fig. 3), previously noted.

In the operation of the set as either a t'rans mitter or a receiver there is utilized an antenna I38 of telescopic or disappearing type which is assembled as a part of the chassis unit 52 (Figs. 6, 9, 10, 12 and 16). The lower section I31 of the antenna I36 is slidably supported in a channel or U-shaped insulating member I38 extending longitudinally of the chassis unit 52. The end I39 of the channel member is supported in the end member 58 of the chassis unit (Figs. 6 and 13). The opposite end I of the channel member I38 is supported on the antenna coil LI by conductor means indicated generally as I42 and which will be later fully explained. The lower end of the antenna section I31 (Figs. 6 and 17) is provided with an insulating projection I44 having a leg portion I46 inserted within the antenna section I38 and retained therein as by rolling, or clamping at I41. The leg portion I48 seals the end of the antenna section I31 to. prevent any moisture within the section I31 from passing outwardly therefrom. The projection I44 is arranged within the open side of the channel member I38 and is slidable therein.

As shown in Fig. 6 the chassis unit is provided with a power switch I48 of toggle type having an actuating arm I49 of substantially L-shape projecting outwardly from the supporting portion 89. The cross arm portion I5I of the actuatin arm I49 is of a substantially arcuate shape and is provided with laterally projecting extensions I52 and I53 at each end thereof. The projection I44 on the antenna section I31 is arranged intermediate the projections I52 and I53 so as to be selectively engageable with one of said projections on linear movement of the antenna section I31 in reversed directions. In the present invention the toggle switch I48 controls the supply of energy to the chassis unit 52 and hence to the set. When the antenna section I31 is in its position shown in Fig. 6 the actuating arm I49 is in a position for cutting all the supply of energy to the chassis unit 52, thereby rendering the set inoperative. On movement upwardly of the antenna section I31, as viewed in Figs. 6 and 10, the extension I44 engages the projection I53 and moves the actuating arm I49 upwardly to a position providing for the supply of energy to the chassis unit. On continued movement upwardly of the antenna section I31 the extension I44 is moved out of engagement with the projection I53 to permit the antenna section I31 be- 'sion I 44 engages the 13 ing slidably moved outwardly from the channel member I38. n upward movement of the actuating arm, however, the projection I32 is moved into the path of movement of the extension I44, so that on a reversed movement of the antenna section I31 downwardly to its contracted position within the channel member I33 the extenprolection I32 to return the actuating arm I49 Fig. 6. It is seen, therefore, that the position of the antenna section I31 relative to the insulating member I39 indicates the control positions of the actuating arm I49. Since the extension of the antenna section I31 projects the same outwardly from the housing 40, as will be later explained, a visible indication of the position of the actuating arm I49 is given by the position of the antenna section I31 relative to the housing 40. In actual practice the click of the toggle switch to an operated position is audible to the operator of the set so as to further aid him in determining the control positions of the toggle switch I48.

The conductor means I42, previously mentioned, for supporting the upper end I II oi the channel member I39 on the chassis unit 52 includes a metal ring I56 (Fig. and a metal bracket member I51. The bracket member I51 is provided in one piece which is bent double and formed with a circular portion IE3 at one end and flat portions I09 and I9I at the opposite end thereof adapted for back to back engagement (Fig. 14). The arcuate portion I58 is extended about the antenna section I31 and is formed at one end I90 with wiper portions I62 (Figs. wand which are retained in pressing engagement against the antenna section I31 by a spring member I83 extended about the antenna. The conductor means I42 includes also a contact member I64 (Figs. 14 and 15) positioned between the portions I39 and iii of the member I51 and having a plurality of spring fingers I66 extended into an opening I81, formed in the arcuate portion I03 oi the member I51, and in pressed engagement against the antenna section I31. The portions I59 and IBI oi the member I51 and the contact member I34 are secured together by a rivet I 93 supported in a base portion I69 which serves as a. socket for the antenna coil LI previously noted. The socket IE9 is supported in the portion 89 or the irame member 95, an insulating portion "I being arranged intermediate the conductor means I42 and the socket I69 to properly position the conductor means I42 relative to the antenna I33.

The conductor member I01 is formed at the end I12 thereof (Fig. 10) with projections I13 adapted to be positioned within the ring member I 56, the ring member I39 thus functioning to lock the member I01 with the channel member I38. 'By virtue of this construction the antenna I36 is positively connected electrically with the antenna coil LI without the use of any wires. Short circuiting and replacement troubles inherent with movable wires connected to telescopic type antennas are thus completely eliminated. The extension of the antenna section I31 from the channel member I39 is defined by the engagement of the extension portion I44 with the metal ring I53 of the conductor means I42.

A single control switch I92 assembled as a part of the chassis unit 02 is used to completely change over the operation of the combination set from its function as a receiver to a'transmitter and vice versa. The switch I92 (Figs. 6

to its position indicated in 14 and 8) extends longitudinally of the chassis unit 02 and to one side thereoi' across the tubes TI-TS, inclusive. The switch I92 includes a stationary insulating member I93 01 fiat form and a movable insulating member I94 also of flat form and arranged for linear movement relative to the stationary member I93. Extending in linear alignment and arranged in a spaced relation longitudinally of the stationary member I93, are contacts I having engaging fingers I91 and I98 (Fig. 31). As illustrated for the switch contact I99a in Fig. 8, the stationary member I93 is formed with an aperture I99 for receiving therein the finger portion I91 of the switch contact IBM. The finger portion I91 is thus retained substantially in the plane of the stationary member I93. It is to be understood, of course, that the above'construction for the contact I96a is similar for all of the contacts I96.

The movable member I94 carries contacts 201 of substantially L-shape having a leg portion 202 extending through a corresponding slot 203 formed in the stationary member I93. The end 204 (Fig. 31) of the leg portion 202 is anchored in the movable member I94 so as to be retained in a fixed position thereon. A second leg portion 206 substantially normal to the leg portion 202 is projected laterally away from a correspond ing slot 203 for positioning between the fingers I91 and I98 of corresponding contacts I96. By virtue of the finger I91 being substantially in the plane of the stationary member I93, the. leg portions 206 are slidably supported for movement on the member I93 and through the finger portions I91 and I98 whereby to slidably support the movable'member I94 on the stationary member I93. It is seen, therefore, that on linear movement of the movable member I94 relative to the stationary member I93 the contacts 20I are moved relative to corresponding contacts I96 to control the energization of the circuits associated with the contacts I93. Contacts on the station ary member I93 not engaged by any contacts 20I on the slidable member I93 are indicated at 200. These contacts 200 are merely the lugs for other circuit connections.

The operation of the switch I 92 is manually controlled by a manually operated unit 201 operatively supported on the housing 40 and to the outside thereof (Fig. 31). The unit 201 includes toggle or extensible means 208 comprising a pair of members 209 and 2 of substantially arcuate shape which are pivotally connected together at their adjacent ends by axis means 2I2. The end 2I3 of the'toggle member 2 is pivotally connected by axis means 2I4 with a bracket member 2 I6 secured to the housing 40 by a screw Or the like 2 I 1 so that the end 2 I3 is in a fixed position relative to the housing 40. The end 2I8 of the toggle member 209 is pivotally connected by axis means 2I9 with a linearly movable member 22I which is slidably supported on the housing 40. The linear movement of the slidable member 22I is in the same direction as the linear movement of the movable member I94 of the switch I92, the member 22I having guiding rim portions 223 thereon for receiving a guiding member 224 secured by a screw 226 to the housing 40. On pressing the t 'gle means 209 toward the right, as viewed in Fig. 31, the pivotal connection 2I2 between the toggle members 209 and 2 is moved in an arcuate path which is substantially normal to the direction of linear movement of the slidable member 22I and hence to the direction of linear movement of the switch member I94. This movement of the toggle means 208 linearly moves the end 2I8 of the toggle member 209 to in turn move the slidable member 22I in a linear direction, The position of the parts of the manually operated unit 201 when the toggle means is in a depressed condition is shown in dotted lines in Fig. 31. The movement of the pivotal connection 2I2 is limited by a cushioned bumper 22'I carried on the housing 40 and secured thereto by the screw 2 I I. Y

The slidable member 22I has an extension 228 thereon which extends through an opening 230 formed in the housing 40'. This extension 228 is in abutting engagement with a projection 229 secured to the movable switch member I94 and extending laterally therefrom through a, slot 23I formed in the stationary switch member I93. On movement of the pivotal connection 2I2 to the right, as viewed in Fig. .31, the extension 228 on the slidable member 22I is moved downwardly to in turn engage the projection 229 for movement therewith to their positions shown in dotted lines in Fig. 31. This downward movement of the projection 29 in turn linearly moves the movable member I94 in one direction relative to the stationary member I93 and hence the contacts relative to the contacts I96 to control the radio circuits.

On release of the toggle means 208 the toggle member 2 is initially moved by a spring member 232 out of a binding position with the toggle member 209. The continued movement of the toggle means 208 to its unoperated position is accomplished by a tension spring 233 (Fig. 8) connected at one end to the stationary member I93 and at its opposite end to the movable member I94, the spring being partially positioned within a slot 234 formed in the stationary member I93. This action of the spring member 233 linearly moves the member I94 in an opposite direction relative to the member I93, with the engagement of the projection 229 with the extension 228 on the slidable member 22I returning the toggle means 208 to an idle position. When the manually operated unit 201 is in the position indicated in full lines in Fig. 31, the set is connected for operation as a receiver. With the toggle unit 201 in the position indicated in dotted lines in Fig. 31 the set is operated as a transmitter. It is seen, therefore, that changing the operation of the set from a transmitter to a receiver is automatically accomplished simply by releasing the operating unit 201 and that the set will operate as a receiver so long as the unit 201 is retained in a depressed position. The change over from receiving to transmitting and vice verse. is accomplished in a minimum of time and without any delay for making adjustments between the receiving and transmitting operations.

The fiat arrangement of the change-over switch means I92 longitudinally of the chassis unit 52 and across one side of the tubes TI-T5, inclusive, provides for the contacts I96and 20I corresponding to an associated tube being substantially adjacent such tube without projecting any appreciable distance laterally from the chassis unit 52. By virtue of a tube and its associated'contacts being adjacent each other only very short leads or connections are required for connecting the contacts of the switch I92 into the tube circuits so as to substantially reduce the circuit losses resulting from long connections. A transparent insulating member 239 (Fig. '7) is arranged in a superposed relation with the switch unit I92 and is secured at each end thereof to the The chassis unit,

radio chassis 52. The transparent insulating member 239 is adapted to have applied thereon suitable markings, indicated as 24! (Fig. 6), to facilitate the assembly and checking of the tube circuits.

From a consideration of Figs. 6, 9 and 11 it is seen that the chassis unit 52 is completely constructed as a pie-assembled unit which is of a substantially rectangular cross section over the entire length thereof, All of the resistor and condenser elements for the various tube and circuit arrangements, the antenna I36 and the change-over switch I92, are relatively arranged so as to be confined within a space defined substantially by the transverse and. longitudinal dimensions of a tube and associated socket portion. including the change-over switch I92 and the antenna I36, is thus adapted to be removed from or inserted within the housing 40 as a complete and compact package.

In connection with the insertion of the chassis unit 52 within the housing compartment 48 it is seen from Fig. 31 that the projection 229 on the the housing.

With reference to Figs. 6 and 16 it is seen that the upper end 242 of the antenna I36 extends longitudinally beyond the end I27 of the chassis unit frame member 95. In the assembly of the chassis unit 52 within its corresponding compartment 48 in the housing 40 the end I2'I thereoi is initially inserted within the compartment 48 and the antenna end 242 extended through an opening 243 provided in the housing cover TI. 'i he opening 243 has a threaded annular rim or wall portion 244, the antenna I36 being spaced from the cover I? and the flange 244 by an insulating member 246 having one end 24'! inserted within the flange 244 and about the antenna. The opposite end 248 of the insulating member 249 carries a rubber grommet 249 which is fitted about the antenna I36 to prevent moisture from passing along the antenna into the housing 40. As illustrated in Fig. 2 the threaded annular flange 244 about the antenna I36 is adapted to receive in threaded engagement thereon a cap member 25I for covering the antenna end 242 when the set. is not in use. When the antenna I36 is being used the cap 26I is threadably en-. 'gaged with a threaded holding flange 262, the

position of the cap in connection'with the flange :32 being shown in Figs. 1 and 3 2. When the set is not in use, therefore, the passage of any moisture about the antenna I36 or injury to the anttnna is positively eliminated by the protector cap 26L The cap ZBI may be attached to the cover I? by a chain or the like 263 to prevent the loss thereof. Referring toFig. 1 it is seen that the set is capable of use while the operator is in motion. Securing of the cap 26I| with the hoder 262 prevents any rattling of the cap when the set is so used.

The cover 11, the housing 40 and the chassis unit 52 are maintained in relative assembly posi- 17 partment 48 in a substantially flush fit with the housing endll. The plate 58 is somewhat larger than the cross sectional area of the compartment 48 so that the peripheral portion thereof indicated at 254 engages the partition member 48 when the chassis unit 52 is positioned within the compartment 48. Withv the chassis unit in the compartment 48 a threaded aperture 255 (Fig. 16) provided in a boss portion 258 on the frame member 95 at the end I21 thereof is in coaxial alignment with an aperture 251 in the housing cover 11. On tightening of a screw 258, which is extended through the aperture 251 for threaded engagement in the threaded aperture 258, the side plate 58 of the chassis unit 52 is drawn against the end of the partition member 43 and the cover 11 is firmly secured to the chassis unit 52 and clamped in closing engagement with the housing 40 at the end 42 thereof. The single screw 258, therefore, in junction with the cooperating action of the chassis unit 52 relative By virtue of this sealed is incapable of to the partition member 43 functions to securely lock the cover 11 in a closed position while acting also to retain the chassis unit 52 in a fixed position within the housing 40. The cover 11 is integrally formed with an apertured ear portion 268 for connection with a strap 291 by axis means 261 (Figs. 16 and 32 to be later noted.

Moisture is prevented from entering the housing 40 from about the cover 11 by a gasket 25I positioned within a peripheral groove 253 integrally formed in the cover 11 (Fig. 16). Thus when the cover 11 is positioned over the housing end 42 the gasket 253 engages such housing end to seal the same. The cover 66 for the housing end 4! is adapted for sealing engagement with the housing by means of a gasket 268 received in a marginal groove 2'69 integrally formed in the cover 66 (Fig. 5). On tightening of the locking means 1| the gasket 268 is clamped against the housing end 4| in an obvious manner. The passage of any moisture into the housing 40 from about the manually operated unit 281 for the change-over switch I92 is prevented by a rubber hood 2' having a central portion preformed to a shape corresponding to the shape of the toggle means 201 when the same is in a rest position and a fiat rim portion 212 for fitting against the housing 40 (Figs. 3 and 31). The rim portion 212 is clamped against the housing at by a clamping plate 213 having an aperture 214 therein for receiving the toggle means 281 and the central preformed portion oi the gasket 21!, the plate 213 being secured to the housing it by screws or the like 218.

The earphone unit 62, previously mentioned, is received within a housing projection 69 which is of ring shape and peripherally threaded at its open free end 213 (Figs. 32 and 33). The unit 62 is essentially a dynamic speaker used for receiving purposes, and includes an annular body portion 214 receivable within the projection 80 and a diaphragm 216 attached to an annular metal rim portion 211 extending peripherally be yond the periphery of the annular body portion 214. The diaphragm 216 is coated with a suitable water repellent material so as to make the same impervious to moisture. A rubber gasket 218 is positioned intermediate the free end 213 of the projection 69 and the rim portion 211. A perforated insulating cap 219 is threadably engaged with the end 213 for closing the open side of the projection. When the cap 219 is threaded on the end 213 the inner surface thereof engages the rim portion 211 to clamp the rub- 18 her mm m in sealing encasement with the rim 211 and the end 218 of the projection 60. engagement and the water resistant character of moisture is prevented from entering the housing portion 88 while the moisture contacting the diaphragm 218, through the perforated cap 219,

injuring the same.- I The microphone unit 88 (Figs. 32 and 34) is receivable within the an'nularhousing portion or projection 88 and includes an annular body pore tion 281 and a microphone diaphragm 282. A protector diaphragm 288 is composed of a, waterproof materlal, which does not interfere with the passage of sound waves to the microphone diapragm 282, and is arranged in a superposed relation with respect to the microphone diaphragm 282 but spaced therefrom by a spacer ring 284. In one commercial embodiment of the invention the protector diaphram 282 is composed of a rubberized cloth having a thickness of approximately .007", with the spacer ring 284 being about 1%" thick. The spaced assembly of the diaphragm 282 and 288 is retained by a rubber gasket 288 of annular-shape having an inwardly extending lip portion 281 at one end extended partially about the protector diaphragm 283 and a lip portion 288 at the opposite end thereoffor fitting about a shoulder 288 provided on the body portion 28L The microphone diaphragm 282 is thus completely enclosed by the gasket 288 and the protector diaphragm 288. The gasket portion 281 is ofa greater diameter than the diameter of the open end 288 of the housing portion so that when the unit 68 is positioned within the portion 65 the gasket portion 281 fits over the end 289. A perforated cap 281 of insulation material is threadably engageable with the end 289 of the housing portion 85 and when screwed thereon clamps the gasket 286 against the housing end 289 to completely seal the microphone unit 63. A metallic ring 292 may be positioned intermediate the cap member 28i and the gasket 286 to prevent any twisting action of the gasket by the cap member when the cap member is being tightened.

From a consideration of Figs. 1, 2 and 32, it is seen that the housing portions Bil and 65 project from a common side of the housing 49 while the manually operated unit 281 projects from a next adjacent side of the housing 49. The housing portions so and 85 are inclined toward each other and are relatively spaced to provide for their use in the manner of a teiephone set as indicated in 1. In other words with the housing 49 supported one hand of the operator the microphone unit 53 is positioned near the operator's mouth While the earphone unit 32 is positioned near one of his ears. In the commercial embodiment of the invention previously mentioned, the housing 4!] is about a foot long and approximately three inches square with the weight of the entire unit being only about five pounds. The housing 40 is thus capable of being easily grasped in one hand of the operator and by virtue of the light weight or the complete set can be readily and simply supported in an operating position which is common for both receiving and transmitting. The operating unit 281 for the change-over switch I92 is arranged relative to the housing portions 88 and 85 so as to be positioned below the hand of the operator which is used in holding the set in its operating position, as shown in Fig. 1. By merely opening and closing the hand, therefore, the unit 281 is operated to control the changethe diaphragm 218 

